Page:The British Warblers A History with Problems of Their Lives - 5 of 9.djvu/43

 the same purpose is unnecessary, or, to state it in another form, the primary object of the law of territory to the individual male is to enable it to secure a mate; it is a form of natural selection in so far as the stronger males only, on the average, will produce offspring, but this form of natural selection can in no way account directly for the development of the colouring of the feathers, vocal powers, or gorgeous plumes. The primary object of sexual selection to the individual male is also to enable it, by reason of any particular attractiveness, to secure a mate, and it thus attempts to explain the development of those secondary sexual characters. But there never could have arisen in Nature, pari passu, two wholly dissimilar struggles, both having the same purpose in view—namely, the attainment of reproduction by the individual. This, as it seems to me, is the position with regard to the second proposition of the theory of sexual selection, and I fail to see how it can by any means be possible for the one process to work with advantage side by side with the other. And if it be asked whether it might not be possible for there to be a further selection by the females of those males that were victorious in battle. I should reply as follows: Firstly, that such a selection would presuppose a large preponderance of males, which supposition would by no means be justified, especially when we bear in mind the fact that even the assumption that males are in the majority rests on no very secure foundation; secondly, that, inasmuch as ex hypothesi the more demonstrative males must always be the stronger, a law of battle to attain the same end would be superfluous; this requires further explanation. That the female prefers one male before another on account of some special adornment is not now regarded as probable by those who still hold to the theory of sexual selection as affording the most reasonable interpretation of the facts, but that she is unconsciously excited by the one that is the more demonstrative, and that the demonstration is in proportion to the strength and consequently to the development